Armored cable



Oct. 28, 1930. A O HOEFTMANN R6. 1?,850

.ARMORED CABLE Original Filed Jan ZINC STRIP ZINC STE]? Ju'rr: FILLER WATER PROOF covEE LEAD SHEET TAPE 0R INSULA Reissued 28 1930 UNITED STATES PATENT- "OFFICE ALEXANDER O. HOEFTMANN,

F WORCESTER, MASSACHUSETTS, ASSIGNOR TO THE AMERICAN STEEL AND WIRE COMPANY OF NEW JERSEY A CORPORATION OF NEW JERSEY ARMOBED CABLE reissue filed June 21 This invention relates to the construction of electric cables and-more particularly to the constructionof cables requiring a protecting armor, such as underground, aerial and submarine cables.

One object of the present invention is to provide a cable of this class with a plurality of layers of sheet metal armor separated from each other by a cushion or layer of jute or the like to relieve a blow-or compression of the inner armor when such blow or compression is exerted on the outer armor.

Another object of my present invention is the construction of cables of the above types having a metallic non-magnetic armor constructed and arranged to permit the use of an exploring coil in localizing breaks or' 1igaults,as they are commonly termed, in cales. Y

Another object of the invention is the provision of an armored cable having the novel construction, arrangement and combination of arts and materials illustrated and descri ed and specifically pointed out in the appended claims.

Referring now to the drawing forming part in which my invention is of this specification, shownsufiiciently to enable those skilled'in the artto understand the construction and operation thereof, Figure 1 is a plan illustrating an armored my invention.

Figure 2 is an shgrwn in Figure 1 h igure 3 is a ia ramni' ic'p an, ereinafter described. g 9% l l Figured is a plan of an exploring coil and receiverused in detecting breaks and faults Tin armored cables. 40 I j In the, accompanying drawings, the nuiner'al 1O designates the conductors of my improvedcabler These conductors 10 may be made of strands instead of single wires, as

shown, and the cablesmay have but a single conductor in lieu of the plurality of conductors shown. The conductors 10 are covered with a layer of insulatory material 11 which, in tur n,'is covered with tape 'or braid 12, and the insulated and taped or braided conductors 10' are surrounded with a jute filler 12 and electric cable embodying.

end elevation of the cable break in a cable,

19, 1927, Serial No. 689,695, filed January 31,- 1924. Application for 1929. Serial No. 372,701.

enclosed-within a lead sheath 13. Obviously, the sheath 131 may contain one or any desired number of conductor-s10. The sheath 13 is then provided with a covering 14 formed of jute or similar fibrous non-conducting material.

Surrounding the jute covering 14 is a sheet metal non-magnetic armor, this armor pref erably being formed of two layers of helicalwound strips of zinc 15 and 16, the outer y layer 16 being staggeredwith respect to the inner layer 15, so as to overlap the helical joint formed by the abutting edges of the strip 15, and being separated from the inner layer by a cushion 17 of jute or the like which is laid up between the layers of armor. 17 serves to relieve a blow orpompression on the inner layer when such blow or compression is exerted on the outer layer. The outer layer of armor 16 is enclosed within an .external covering 17 a made of any suitable material and made water-proof or fire-proof, or both,vin any desired known manner. It will be understood that if the non-magnetic feature'is notdesired the armor may be composed of steel or any other suitable-metal."

With cables made in this manner localized 'by the use of a suitable detector, without the necessity of removing the defec- The cushion any breaks 'or faults in a cable maybe easily and quickly tive cable fromthe ground and with a minimum amount of excavation.

In determining the location of a fault or a detector such asis shown in Figures 3 and 4 will be employed, this detector comprising'an exploringncoil 18- connected by wires 19 and 20 to atelephone receiver 21. (See Figure 4.) In localizing a fault or break in a cable embodying my invention, a point 22 on one conductor 1O connection 23, and an adjacentpoint 29 in a second conductor 10 will be connected-to a connection 28. The connection 23 is by one end to a source of intermittent current 24, this source also being attached to one end of a connection 25. The other end of theconneetion 25 is attached to a commutator or make and break switch 26, the current source 24; and make and break switch 26 being mountwill be connected to one end of a attached ed on a suitable connecting shaftor rod 27.

cable, which may 'be submergedor may be buried in a trench, and which, due to its me-.

tallic non-magnetic armor, allows the magnetic lines of force to be concentrated in the core of the electrically permeable coil .18.

The coil 18, being permeable, causes a buzz in the telephone receiver 21 which will con tinueto sound untilthe fault (indicated at 30,

Figure 3) is reached. When such fault is reached an interruption in the magnetic lines of force .is ca'usedthereby and buzzing in the 1 receiver stops, and thereby indicates to the op erator the location of the fault. The result is not possible with an armor of magnetic material, as the magnetic'armo'r is electrically perstaggered with respect to said inner zinc strip so as to overlap the helical joint formed by the abutting edges of said inner strip, and a weter-proof covering enclosing said. armor.

v 2. A flexible arino'red cable comprising at least one conductor, a lead sheath mounted around and enclosing said conductor, a fibrous covering for said sheath, a metallic armor surroun'dlng' said fibrous covering, said armor comprising innerand outer helically wound zinc strips, and a continuous layer of jute be tween said inner and outer strips adapted to relieve and cushion a. blow or compression on the inner-strip when such blow or compression is exertedon the outer strip, and said outer' strip being staggered "with respect to said inner strip so as to overlap the helical joint formed by the abutting edges of said inner strip.

In witness whereof I have hereunto signed my name;v

' ALEXANDER 0. HOEFTMANN.

meable, which causes themagnetic lines of force to be contained within said magnetic armor and renders the coil 18 and receiver 21 inoperative localizing faults or breaks in the cable.

It will be seen that my improved cable construction provides a metallic armored cable, in which a blow or compression applied to and penetrating the-outer layer of armor will, be

cushioned before reaching an inner layer and thus reduce thelikelihood of it penetrating the inner layer of armor. It will also be seen that my improved cable provides a construction wherein faults may. be quickly localized at a minimum expense and without the neces sity of removing any part of the cable forenamination, all of which will be readily under- .stood and appreciated by those skilled in the art.

Various changes and modifications in the construction and arrangement of the parts ofthe cables made according to'my invention,-

may be'ma'de without departing from the spirit and scope thereof, as defined in the appended claims.

I claims-' 1 l 1. A flexible armoredcable comprising at least one. conductor, a leadsheath mounted around and enclosing said, conductor, a

- fibrous covering for said sheath, a non-magnetic metallic armor surrounding said'fibrous covering, said armor comprising. inner and outer helically wound zinc strips, and a continuous layerof jute between said inner and outer zinc strips adapted to'relieve and cush-' iona blow or compression on the inner strip when such blow or compression is exerted on the outer strip,*said outer zinc' strip being 

